Dental technology has come a long way, but the potentially harmful effects of chemical substances in fillings could make tried-and-true brushing and flossing the safest way to maintain healthy teeth

On a recent trip to the dentist, I was shocked by two things. The first was the pair of thigh-high boots my young female dentist was wearing. The second was the realization that my new white fillings contain Bisphenol A.

Bisphenol A is a hormone-disrupting chemical that has been linked, in very low doses, to cancer. For this reason, it is banned in Canada. The government's recommendations place restrictions on Bisphenol A for use in infant products but according to the Canadian Dental Association, no restrictions are planned for dental materials.

Toxins in Your Teeth

I had been thinking a lot about dental materials since my six-year-old son returned from a dental appointment the week before. His dentist suggested that we fill his back molars with dental sealant. The information package we requested contained photocopied information on the proposed 3M ESPE Supreme Ultra Flowable Restorative. 3M's products include anti-cavity toothpaste, thinsulate thermal insoles, respirator systems and Post-It Notes. A yellow Post-It-Note adhered to the first page read, "Hope you find this info useful."

The first paper in the pile was the product information from 3M. It revealed that the Supreme Flowable Restorative is a low-viscosity, visible light-activated, radiopaque, nano-composite which comes in various tooth shades. It contains bisGMA, TEGDMA and Procrylat resins.

According to the Medical Dictionary Online, bisGMA is "the reaction product of bisphenol A and glycidyl methacrylate that undergoes polymerization when exposed to ultraviolet light or mixed with a catalyst." Methacrylates, according to Wikipedia, are bonding agents and TEGDMA, or triethyleneglycol dimethacrylate, is a chemical that reduces the viscosity of liquids. Polycrylat resins, after some digging, are also called propane dimethacrylate.

This list however does not include the fillers which are made up of "ytterbium trifluoride filler with a range of particle sizes from 0.1 to 5.0 microns." While the rest of the list is somewhat indecipherable, according to the Hazard Code in the Safety section of the online Chemical Book, ytterbium trifluoride is rated T.Xi, whereas T equals toxic and Xi stands for irritant. 

According to the Chemical Book's Risk Assessment, ytterbium trifluoride is very toxic by inhalation, very toxic in contact with skin, and very toxic if swallowed, which, in my opinion, does not bode well for dental products.

More information reveals that contact with water liberates toxic gas. In the Precautionary Information for Patients, 3M states that this product may cause an allergic reaction "by skin contact in certain individuals." And in the Limitation of Liability 3M asserts that "Except where prohibited by law, 3M ESPE will not be liable for any loss or damage arising from this product whether direct, indirect, special, incidental or consequential regardless of the theory asserted, including warranty, contract, negligence or strict liability."

The next pages were from the Canadian Dental Association (CDA). Unlike the tiny print that took lots of research to understand, the CDA cites an article published in Pediatrics (J Can Dent Assoc 2010, 76a129) which reviewed the existing literature on possible BPA exposure from dental materials and concluded that "On the basis of substantiated preventive benefits of resin-based dental sealants and given the brevity of elevated exposure to BPA after sealant application, we recommend continuing application of resin-based sealants." 

CDA suggests that dentists use a mild abrasive after application and have older children gargle with tepid water for 30 seconds or alternatively the dentist should wash the sealant surface with an air-water syringe while suctioning fluids and debris from the child's mouth.

Dental Fillings: Silver or White?

With all of this dental material information was whirling in my mind, I was lowered onto my back in the newly installed, reclining dental chair. Before giving me any freezing, my well-heeled dentist asked if I would like a white or silver filling.  

Silver fillings, aside from being unsightly, are nearly equal parts liquid mercury and powder - made from either silver, tin, copper, zinc or "other" metals. Despite the presence of mercury, a poisonous metal, The Canadian Dental Association website points out that silver fillings have been used for over 150 years and according to reports, they don't make people sick.

Silver or white?

I asked for assistance. After some discussion, more conversational than professional, between my dentist and the hygienist, it was decided that short people who laugh with their mouths open wide should opt for white fillings. The Bisphenol A, they assured me, was only present in the off-gasing, not in the actual material of the filling so it was "well within safety margins."

For me, vanity won over. I chose white composite fillings. My son's dental sealants, though, are going to be replaced by good 'ole flossing and brushing. 

Prevention is far less toxic than the list of chemical substances on 3M's product page. What worries me is the accumulation of toxic substances not just in dental materials but elsewhere in our lives. So I will keep reading the fine print and trying to connect the toxic dots.

Read the toxic fine print on your food.

Teresa Goff is a freelance writer and broadcaster. As the mother of one very allergic boy and one very energetic boy, she has learned how to make food out of nothing at all while playing lego and doing two art projects at once.